1. Field of the Invention
The present invention pertains to an electrohydrodynamic (EHD) evaporator device, and particularly to an electrohydrodynamic evaporator device having an enhanced thermal transport efficiency through generating an EHD effect by use of an electrode.
2. Description of the Prior Art
To improve thermal exchange efficiency of an evaporator, increased surface area, number and associated arrangements of evaporator tube are generally suggested. For example, threads may be added to an interior wall of the evaporator tube to enhance the thermal exchange efficiency. However, this manner may only increase the thermal exchange efficiency passively with results of limited heat exchange effect, prolonged process time and larger volume and weight of the evaporator. Such evaporator may be seen in, for example, the R.O.C. patent no. 546459. In this patent, it is disclosed that refrigerant is provided to cool down a plurality of thermal conducting tubes in a bundle so that heat exchange may be induced between the refrigerant and the thermal conducting tubes and thus the thermal conducting tubes may be cooled down. This cooling device is characterized in that the thermal conducting tubes are grouped and the thermal conducting tube groups are separately arranged.
In the R.O.C. patent no. 543759, an improved fin structure of the evaporator is disclosed in which a saw-like structure is provided at a bottom of the fin. By means of the saw-like structure along with gravity of congealed water generated in the evaporator, the congealed water may be speeded up to flow to a tip of the saw-like structure and then come off from the fin.
In another R.O.C. patent no. 482003, an improved evaporator is disclosed in which a distance liner is provided in a barrel having an inlet and an outlet, the barrel having a cover disposed thereon and the distance liner having a cooling tube disposed there around and extending outward through the cooling tube. This evaporator is characterized in that a hollow tubing element is contained in the distance liner and a spiral piece is welded to an outer surface of the tubing element along a spiral direction so that a spiral tube is formed. And the cooling tube is coiled among the spiral piece in the spiral tube.
However, such evaporator has the following disadvantages. 1. Only a passive improvement in structure is provided and the heat exchange efficiency may not be self-controlled. 2. Since the evaporator may only be improved in structure, dimension, volume and weight of the evaporator may not be efficiently reduced. 3. The amount of the refrigerant required for the evaporator may not be reduced.
In view of these problems encountered in the prior art, the Inventors have paid many efforts in the related research and finally developed successfully an electrohydrodynamic (EHD) evaporator device, which is taken as the present invention.